Square Bore Agricultural Bearings

BMT Bearings manufactures Square Bore Agricultural Bearings engineered for heavy-duty farm machinery, including disc harrows, seeders, and harvesters. The precision-machined square bore fits directly onto square shafts, eliminating slippage and secondary locking components. Combining GCr15 steel construction (HRC 60–64) with an IP69K-rated sealing system, these bearings effectively resist mud, fertilizers, and impact loads. Produced under ISO 9001 and IATF 16949 standards, BMT Bearings provides standard models like GW208PPB5 as well as custom OEM configurations.

What Is a Square Bore Agricultural Bearing?

A Square Bore Agricultural Bearing is a specialized rolling-element bearing designed to mount directly onto square transmission shafts without relying on additional locking collars, adapter sleeves, or set screws. The inner ring features a precision-machined square opening that matches the profile of the drive shaft, enabling direct torque transmission during operation. This configuration prevents rotational slip between the shaft and the inner ring under heavy mechanical loads. BMT Bearings manufactures Square Bore Agricultural Bearings, such as the GW208PPB5 model, to deliver localized axial and radial load support across severe agricultural operating conditions.

Key Product Features

Square Bore Design

The inner ring features an internal square profile manufactured to tight dimensional tolerances, allowing direct slide-on fitting over standard square shafting. This interface eliminates relative rotational movement, ensuring positive engagement under high rotational torque.

Shaft Locking Structure

The direct geometric engagement between the square shaft and the bearing bore eliminates the requirement for secondary locking mechanisms. The drive force is transferred directly across the flat surfaces of the square bore, preventing shaft slippage during sudden direction changes or torque spikes.

Sealing Structure

Equipped with an IP69K-rated triple-lip contact sealing system, the assembly prevents foreign material from entering the internal raceways. The heavy-duty seal design blocks mud, slurry, soil particles, fertilizers, and moisture while retaining internal grease during high-pressure equipment washing.

Housing Construction

The outer bearing unit utilizes a high-strength cast iron housing combined with a hardened steel liner structure. This construction resists external shock loads, severe vibration, and structural deformation encountered during field operations.

Bearing Material and Precision

The rolling elements and bearing rings are produced from high-carbon chromium bearing steel (GCr15/AISI 52100). Controlled heat treatment processes yield a surface hardness of HRC 60–64.

Technical Parameters

BMT Bearings’ Square Bore Agricultural Bearings series includes 10 continuous models (SAB-001 to SAB-010), with main dimensions (bore d x outer D x width B in mm), dynamic load rating (C in kN), and static load rating (C0 in kN), per ISO 3228 for agricultural applications.

Agricultural Operating Conditions

Load and Speed Requirements

Square Bore Agricultural Bearings are designed for moderate rotational speeds paired with continuous radial forces and intermittent axial shock loads. The internal raceway geometry accommodates multi-directional force vectors generated by soil engagement tools and mechanical linkage mechanisms.

Environmental Resistance

The external surfaces are treated with an anti-corrosion coating to resist exposure to moisture, agricultural chemicals, and soil acids. Internal raceways are lubricated with a high-performance synthetic grease engineered to operate within a temperature range of -35°C to 130°C.

Bearing Selection

When selecting Square Bore Agricultural Bearings, consider the following technical parameters:

Shaft Dimensions: Exact cross-sectional dimensions of the square shaft.

Operating Loads: Peak radial force, axial thrust components, and impact frequency.

Environmental Exposure: Degree of soil contamination, moisture exposure, and chemical contact.

Housing Mounting: Bolt-hole spacing, flange geometry, and mounting surface flatness.

Installation Method

1.Clean the square shaft end and remove burrs, corrosion, or debris.

2.Apply anti-seize compound evenly across the shaft surface.

3.Align the square bore of the bearing with the shaft profile and slide the assembly into position without forcing or hammering the inner ring.

4.Secure the housing structure to the equipment frame using standard fasteners.

5.Retain the assembly axially on the shaft using a lock nut or retaining ring, torqued to 20–30 Nm.

6.Verify that maximum angular shaft misalignment does not exceed 1°.

Lubrication and Maintenance

Square Bore Agricultural Bearings are pre-lubricated with synthetic grease. For continuous operation in severe conditions, apply NLGI No. 2 lithium-complex grease every 250 operating hours through the provided grease fitting. Ensure operating temperatures do not exceed 90°C during continuous service. Store uninstalled bearings in a dry, temperature-controlled environment within their original packaging.

Applications

The Bore Agricultural Bearings are integrated into transmission and rotating mechanisms across various farm machinery, including:

1.Disc harrows and tillage equipment

2.Seed drills and precision planters

3.Fertilizer spreaders and manure applicators

4.Combine harvester headers and threshing systems

5.Balers and rotary cutters

Manufacturing and Quality Control

BMT Bearings produces Square Bore Agricultural Bearings utilizing automated conveyances, CNC grinding production lines, and automatic assembly systems. Quality control protocols cover:Dimensional accuracy testing of the inner square profile, Hardness testing of raceways and rolling elements, Radial clearance measurement, Dynamic noise and vibration spectrum analysis and Surface roughness verification.

OEM and Custom Services

BMT Bearings provides engineering and manufacturing services for customized Square Bore Agricultural Bearings. Custom capabilities include Non-standard square bore dimensions and keyway modifications, Specialized sealing configurations and shield materials, Custom housing geometries and mounting patterns, Customized grease fills for extreme temperature ranges and Private label marking and specialized export packaging.

Why Choose BMT Bearings

BMT Bearings brings over 20 years of manufacturing experience to the production of precision rolling elements. Operating 100 sets of automatic grinding lines with an annual capacity reaching 100 million units, the company maintains strict compliance with ISO 9001 and IATF 16949 quality systems. BMT Bearings delivers consistent dimensional tolerances and traceable batch quality across both standard catalog items and custom OEM components.

FAQ

What is the purpose of the square bore design? 

The square bore design allows the bearing to lock directly onto a square shaft, enabling positive torque transmission without requiring set screws, lock collars, or adapter sleeves.

What temperature range can Square Bore Agricultural Bearings operate in? 

When packed with synthetic grease, Square Bore Agricultural Bearings operate within a temperature range of -35°C to 130°C. Continuous operational temperatures should remain under 90°C.

Are custom dimensions available for the Bore Agricultural Bearings? 

Yes. BMT Bearings offers OEM and custom manufacturing services for non-standard square bore sizes, custom housing configurations, and specialized sealing arrangements based on customer technical drawings.

What quality certifications apply to BMT Bearings' manufacturing processes? 

BMT Bearings operates under registered ISO 9001 and IATF 16949 quality management systems.

What maintenance is required for the Bore Agricultural Bearings? 

Re-lubricate the unit with NLGI No. 2 grease every 250 operating hours, ensure proper shaft alignment (≤1° misalignment), and maintain clean sealing surfaces.

Technical Parameters

BMT Company’s GW208PPB5 Square Bore Agricultural Bearings series includes 10 continuous models (SAB-001 to SAB-010), with main dimensions (bore d x outer D x width B in mm), dynamic load rating (C in kN), and static load rating (C0 in kN), per ISO 3228 for agricultural applications.